将 Python AES 加密路由移植到 Golang

Question

我正在尝试将以下 Python AES 文件加密例程移植到 Go：

def derive_key_and_iv(password, salt, key_length, iv_length):
    d = d_i = ''
    while len(d) < key_length + iv_length:
        d_i = md5(d_i + password + salt).digest()
        d += d_i
    return d[:key_length], d[key_length:key_length+iv_length]


def encrypt(in_file, out_file, password, key_length=32):
    bs = AES.block_size
    salt = Random.new().read(bs - len('Salted__'))
    key, iv = derive_key_and_iv(password, salt, key_length, bs)
    cipher = AES.new(key, AES.MODE_CBC, iv)
    out_file.write('Salted__' + salt)
    finished = False
    while not finished:
        chunk = in_file.read(1024 * bs)
        if len(chunk) == 0 or len(chunk) % bs != 0:
            padding_length = (bs - len(chunk) % bs) or bs
            chunk += padding_length * chr(padding_length)
            finished = True
        out_file.write(cipher.encrypt(chunk))


def decrypt(in_file, out_file, password, key_length=32):
    bs = AES.block_size
    print(bs)
    salt = in_file.read(bs)[len('Salted__'):]
    key, iv = derive_key_and_iv(password, salt, key_length, bs)
    cipher = AES.new(key, AES.MODE_CBC, iv)
    next_chunk = ''
    finished = False
    while not finished:
        chunk, next_chunk = next_chunk, cipher.decrypt(in_file.read(1024 * bs))
        if len(next_chunk) == 0:
            padding_length = ord(chunk[-1])
            chunk = chunk[:-padding_length]
            finished = True
        out_file.write(chunk)

我编写了以下 Go 例程，但我不太能够让它工作。我正在尝试让加密例程在 Go 中为调用 Python 和 C 中的解密的调用者工作，所以我真的只对弄清楚如何让我的 Golang 加密例程工作感兴趣，但已经包含了所有 [=为清楚起见，22=] 位。

我当前的 Go 例程如下所示：

package main
import (
    "crypto/aes"
    "crypto/cipher"
    "crypto/rand"
    "encoding/base64"
    "errors"
    "fmt"
    "io"
    "log"     
    "crypto/md5"  
    "os"
    )


func pyEncrypt(password []byte, pathToInFile string, pathToOutFile string){
    bs := int(aes.BlockSize)
    salt := make([]byte, aes.BlockSize - len("Salted__")) 
    _, err := rand.Read(salt)
    if err != nil {panic(err)}

    key, iv := deriveKeyAndIV(password, salt, bs)   
    block, err := aes.NewCipher(key)
    if err != nil {panic(err)}

    cfb := cipher.NewCFBEncrypter(block, iv)

    fin, err := os.Open(pathToInFile)
    if err != nil {panic(err)}
    defer fin.Close()

    fout, err := os.Create(pathToOutFile)
    if err != nil {panic(err)}
    defer fout.Close()

    _, err = fout.Write([]byte("Salted__")) 
    if err != nil {panic(err)}
    _, err = fout.Write(salt)
    if err != nil {panic(err)}

    for true{
        ciphertext := make([]byte, 1024 *bs)
        chunk := make([]byte, 1024 * bs)
        _, err := fin.Read(chunk)
        if err == io.EOF{
        break
        }else if err != nil{
            panic(err)
        }
        cfb.XORKeyStream(ciphertext, chunk)     
        fout.Write(ciphertext)
    }
}


func deriveKeyAndIV(password []byte, salt []byte, bs int) ([]byte, []byte) {
    var digest []byte
    hash := md5.New()
    out := make([]byte, 32 + bs) //right now I'm just matching the default key size (32) from the python script so 32 represents the default from python
    for i := 0; i < 32 + bs ; i += len(digest) {
        hash.Reset()
        hash.Write(digest)
        hash.Write(password)
        hash.Write(salt)
        digest = hash.Sum(digest[:0])
        copy(out[i:], digest)
    }
    return out[:32], out[32:32+bs] //matching the default key size from Python as that is what the application uses
}

func main() {
    pwd := []byte("test123")

    pyEncrypt(pwd, "/home/chris/pt.txt", "/home/chris/genc.txt")    
}

现在它运行了，大声笑，生成了一个看起来正确的加密文件，Python "decrypts" 没有错误，但它生成了乱码，实际上并没有生成明文。 Python 例程独立工作，但我无法让我的 Golang 加密生成 Python 解密可以解密的输出。为了与调用者兼容，我必须匹配 Python 加密例程。你看到我在我的 Golang 加密例程中做错了什么了吗？非常感谢您的帮助。

Answer 1

这是有效的加密例程：

func pyEncrypt(password string, pathToInFile string, pathToOutFile string){
    bs := int(aes.BlockSize)
    salt := make([]byte, aes.BlockSize - len("Salted__")) 
    _, err := rand.Read(salt)
    if err != nil {panic(err)}

    key, iv := deriveKeyAndIV([]byte(password), salt, bs)   
    block, err := aes.NewCipher(key)
    if err != nil {panic(err)}

    cbc := cipher.NewCBCEncrypter(block, iv)

    fin, err := os.Open(pathToInFile)
    if err != nil {panic(err)}
    defer fin.Close()

    fout, err := os.Create(pathToOutFile)
    if err != nil {panic(err)}
    defer fout.Close()

    _,err = fout.Write([]byte("Salted__"))
    if err != nil {panic(err)}
    _,err = fout.Write(salt)
    if err != nil {panic(err)}

    for true{
        chunk := make([]byte, 1024 * bs)

        n,err := fin.Read(chunk)
        if err == io.EOF{
        break
        }else if err != nil{
            panic(err)
        }

        if n == 0 || n % bs != 0 {//need to pad up to block size :bs
            paddingLength := (bs - n % bs) 
            paddingChr := []byte(string(rune(paddingLength)))
            paddingBytes := make([]byte, paddingLength)

            for i := 0; i < paddingLength; i++{
                paddingBytes[i] = paddingChr[0]
            }

            chunk = append(chunk[0:n], []byte(paddingBytes)...)
        }else{
            chunk = chunk[0:n]//no padding needed           
        }

        ciphertext := make([]byte, len(chunk))
        cbc.CryptBlocks(ciphertext,chunk)
        fout.Write(ciphertext)
    }
}

将 Python AES 加密路由移植到 Golang

Porting Python AES encryption routies to Golang

encryption

cryptography

aes

go